US20190128999A1 - Microwave and millimeter wave imaging - Google Patents
Microwave and millimeter wave imaging Download PDFInfo
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- US20190128999A1 US20190128999A1 US16/171,146 US201816171146A US2019128999A1 US 20190128999 A1 US20190128999 A1 US 20190128999A1 US 201816171146 A US201816171146 A US 201816171146A US 2019128999 A1 US2019128999 A1 US 2019128999A1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/03—Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver
- G01S7/032—Constructional details for solid-state radar subsystems
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/88—Radar or analogous systems specially adapted for specific applications
- G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
- G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/88—Radar or analogous systems specially adapted for specific applications
- G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
- G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
- G01S13/9004—SAR image acquisition techniques
- G01S13/9011—SAR image acquisition techniques with frequency domain processing of the SAR signals in azimuth
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q13/00—Waveguide horns or mouths; Slot antennas; Leaky-waveguide antennas; Equivalent structures causing radiation along the transmission path of a guided wave
- H01Q13/08—Radiating ends of two-conductor microwave transmission lines, e.g. of coaxial lines, of microstrip lines
- H01Q13/085—Slot-line radiating ends
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q21/00—Antenna arrays or systems
- H01Q21/06—Arrays of individually energised antenna units similarly polarised and spaced apart
- H01Q21/061—Two dimensional planar arrays
- H01Q21/064—Two dimensional planar arrays using horn or slot aerials
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q21/00—Antenna arrays or systems
- H01Q21/06—Arrays of individually energised antenna units similarly polarised and spaced apart
- H01Q21/08—Arrays of individually energised antenna units similarly polarised and spaced apart the units being spaced along or adjacent to a rectilinear path
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
- H01Q3/24—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
- H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
- H01Q3/28—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture varying the amplitude
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
- H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
- H01Q3/30—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture varying the relative phase between the radiating elements of an array
- H01Q3/34—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture varying the relative phase between the radiating elements of an array by electrical means
- H01Q3/36—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture varying the relative phase between the radiating elements of an array by electrical means with variable phase-shifters
Abstract
Description
- This invention was made with government support under grant NSF 1011744 awarded by the National Science Foundation—Graduate Research Fellow Program. The government has certain rights in the invention.
- Microwave and millimeter wave imaging utilizing synthetic aperture radar (SAR) is capable of generating high resolution, 3D images of complex dielectric structures for many critical nondestructive testing, biomedical, and security applications. Recently, microwave imaging systems have been developed to make this technology portable with real-time image results, making them suitable for field inspection. Current microwave imaging systems use a transmitter, receiver, microwave multiplexer network(s), and an array of antennas. Electric field measurements on the aperture of the imaging system are made by routing signals between the transmitter, receiver, and a single antenna element one at a time. This results in a rapid electronic raster scan of the array aperture. The conventional ω-k SAR algorithm is then used to generate an image. Another imaging method known as MIMO-SAR (multiple input multiple output-SAR) follows a similar approach. Multiple transmitting antennas illuminate a target, and a separate array of antennas sequentially or simultaneously receive the electric field measurements. Often the transmitting antennas are sequentially switched with microwave multiplexer switches.
- There are a few disadvantages to using microwave multiplexer switches. For instance, they are often expensive, constituting a significant portion of the overall material cost. Also, they incur signal loss between transmitter, receiver, and antenna array, which reduces system dynamic range and hence the quality of images produced. And their operation is frequency limited. These disadvantages become even more significant and further restrictive for very high frequencies in the millimeter wave regime.
- Aspects of the invention relate to an improved microwave and millimeter wave imaging system that does not require microwave multiplexer switches. This constitutes a marked developmental and technical advance over the existing imaging systems employing SAR. Aspects of the invention further relate to the development of an antenna array model without switches and a modification to the ω-k algorithm to properly generate images using the imaging system.
- In an aspect, an imaging system includes an antenna array in communication with a signal source. The array comprises a plurality of antennas by which a signal generated by the signal source is transmitted incident to an object located remotely from the antenna array and by which a signal reflected from the object is received by the antenna array. The signals transmitted by the antennas collectively have an effective electric field resembling a plane-wave within a target region in front of the antenna array. A plurality of detectors each connected to one of the antennas is configured to simultaneously receive the reflected signal and provide an output signal representative thereof. An image processor configured to execute an imaging algorithm generates a multi-dimensional profile representative of the object based on the output signals from the detectors.
- A method embodying aspects of the invention includes transmitting a signal from a source via an antenna array and incident to the object. The signal source is configured to provide an electromagnetic energy source ranging in frequencies up to and including a terahertz frequency range and the antenna array has a plurality of antennas by which the signal from the signal source is transmitted incident to the object within a target region located in front of the antenna array and by which a signal reflected from the object is received by the antenna array. The signals transmitted by the antennas collectively have an effective electric field resembling a plane-wave within the target region. The method also includes simultaneously receiving, by a plurality of detectors each connected to one of the antennas, the signal reflected from the object and providing an output signal representative thereof and generating, by a processor executing an imaging algorithm, a multi-dimensional profile representative of the object based on the output signals from the detectors.
- Other objects and features will be in part apparent and in part pointed out hereinafter.
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FIG. 1 is a schematic diagram of an imaging system in accordance with an embodiment of the invention. -
FIG. 2 is an exemplary image of an ideal point target generated by the imaging system ofFIG. 1 . -
FIG. 3 illustrates an exemplary electric field radiated from antennas of the imaging system ofFIG. 1 . -
FIG. 4A is an image of a metal ball placed at the center, close to an antenna array ofFIG. 1 . -
FIG. 4B is an image of a metal ball placed at center, far from an antenna array ofFIG. 1 . -
FIG. 4C is an image of a metal ball placed at the edge of an antenna array ofFIG. 1 . -
FIG. 5 is a cross sectional image of a metal rod imaged by the imaging system ofFIG. 1 . -
FIG. 6 is a schematic diagram of an imaging system with amplitude and phase shifting elements in accordance with an alternative embodiment of the invention. -
FIG. 7 is a schematic diagram of an imaging system with single pole single throw switches in accordance with an alternative embodiment of the invention. -
FIG. 8 is a schematic diagram of an imaging system with 2-dimensional antenna array in accordance with an alternative embodiment of the invention. -
FIG. 9 is an image of three metal balls placed at different locations relative to the imaging system ofFIG. 8 . -
FIG. 10 is an image of three spheres having different dielectric properties placed at different locations relative to the imaging system ofFIG. 8 . -
FIG. 11 is an image of a key placed in front of the imaging system ofFIG. 8 . - Corresponding reference characters indicate corresponding parts throughout the drawings.
- Referring now to
FIG. 1 , animaging system 100 embodying aspects of the present invention requires no active microwave multiplexer networks thus eliminating a major portion of the hardware and producing a system that is smaller and costs less. Thesystem 100 ofFIG. 1 comprises an antenna array 102 (e.g., a 16 element linear antenna array in the illustrated embodiment). In addition,system 100 comprises amicrowave source 104,data acquisition hardware 108, and a processor 110 (e.g., a personal computer) for image processing. Themicrowave source 104, which has an output frequency programmed by theimage processor 110, outputs a signal that is equally split by a passive divider network 112 (e.g., Wilkinson dividers) and distributed to eachantenna 116 of thearray 102. Thesystem 100 in accordance with the illustrated embodiment produces signals that are emitted from theantennas 116 with substantially equal magnitude and phase. With uniform signal distribution for allantennas 116, an effectiveelectric field 117 radiated fromarray 102 resembles a plane-wave within a target region located in front ofantenna array 102. This pseudo plane-wave impinges on atarget 118, and anelectric field 119 reflected by thetarget 118 radiates back toarray 102. - According to an embodiment,
multiple detectors 120 at an aperture of imaging system 100 (e.g., 32 Schottky diodes inFIG. 1 ), mix the outgoing transmittedelectric field 117 with the incoming reflectedelectric field 119. The output of thedetectors 120 is a low frequency signal that is recorded by thedata acquisition hardware 108. The recorded signals are then sent toimage processor 110 running a modified version of the ω-k SAR algorithm to produce an image oftarget 118 in real-time. - The
detectors 120 mix the receivedsignal 119 with theoutgoing signal 117 down to frequencies much lower than the microwave range (KHz-MHz range) and thedata acquisition hardware 108 multiplexes the down-mixed signal from the detectors to a central analog to digital converter using low-cost, low frequency switches. For anyantenna 116 inarray 102, the signal transmitted byantenna 116 and the signal received bydetectors 120 placed on thesame antenna 116 are approximately at the same position, which allows for the implementation of the ω-k SAR algorithm for image processing. This is a major difference when compared to an imaging system using MIMO-SAR design concepts, where the transmitters and receivers cannot be approximated to the same location. - In an embodiment,
image processor 110 executes a modified algorithm based on the the ω-k SAR algorithm with the equation shown below to generate images from thesystem 100 ofFIG. 1 . While the following derivation is applied for the 1D imaging system, the derivation applies for 2D imaging as well. The ω-k algorithm for a 1D imaging system where eachantenna 116 is performing measurements one at a time, is described as: -
- In this equation, x represents a spatial location along the aperture of
array 102, z represents distance fromarray 102, and f represents the frequencies emitted fromarray 102. Additionally, kx represents the wave number along the x direction. The raw measurement data recorded byimaging system 100 is shown as s(x, f), and the rendered image is I(x, z). Part of the equation, Kz=√{square root over (4k2−kx 2)}, which is the wave number along the z direction, describes how the electric field radiated from oneantenna 116 propagates to the target, and is scattered back and received by thesame antenna 116. An important aspect of this wave number is that it describes both paths traveled by the electric field (array 102 to target 118 andtarget 118 back to array 102). - In the
system 100 ofFIG. 1 ,array 102 radiates a pseudo plane-wave and detectors 120 (e.g., Schottky diodes) simultaneously measure the backscattered signals. The wave number that represents the propagated electric field differs for the path fromarray 102 to target 118 and the path fromtarget 118 back toarray 102, so one simple wave number equation cannot describe both paths. Therefore the algorithm is generalized to become: -
I(x,z)=∫kx (∫x(s(x,f)e −jkx x dx)e j(kf +kb )z)e jkx x dk x (2) - Here, the wave number equation is separated into two quantities: Kz=kf+kb, where kf describes propagation from
array 102 to target 118 (forward), and kb describes propagation fromtarget 118 back to array 102 (backward). The latter is similar to a one-way SAR back propagation, so kb=√{square root over (k2−kx 2)}. Because theelectric field 117 propagated fromarray 102 to target 118 is a pseudo plane-wave, it is described as kf=k. In this modification, the wave is approximated as an ideal plane-wave. It is to be understood that this approximation puts some limitations on the capabilities ofimaging system 100 and a better approximation for the forward propagated wave can be determined through an optimization routine. With a better equation for kf, the limitations on image reconstruction are effectively removed. - In an example, the
imaging system 100 shown inFIG. 1 was used for the simulation model with an operating frequency range of 20-30 GHz. Anideal point target 118 was placed in the middle ofarray 102, andimage processor 110 generated an image by the algorithm as shown inFIG. 2 . The imagingsystem antenna array 102 is located at the top edge of the image. From the image, it is shown that the modified SAR algorithm embodying aspects of the present invention is capable of generating high-resolution images. Preferably, the plane-wave approximation is used within certain distances fromimaging system 100 to maintain the uniform excitation of eachantenna 116 inarray 102 and the resulting antenna array effects. - According to embodiments of the invention, the
antenna array 102 generates a pseudo plane-wave at various distances. An ideal plane-wave has equal amplitude and phase acrossarray 102 for all distances. However, it is to be understood that as the distance fromarray 102 increases, the amplitude of theelectric field 117 becomes less like a plane-wave. Additionally, near the edge ofarray 102, the phase ofelectric field 117 differs greatly from the phase at the middle ofarray 102. - In an embodiment,
system 100 includes a printed circuit board on whicharray 102 is formed of 16 tapered slot-line antennas 116 at an edge of the board. Also at the edge of the board is an array ofdetectors 120, namely, 32 Schottky diodes for measuring the reflectedelectric fields 119. The inputs to theantennas 116 are connected to thedivider network 112, which includes 1:16 passive Wilkinson dividers. -
FIG. 3 shows anelectric field 117 radiating downward fromarray 102. Becausearray 102 in this embodiment is 132 mm wide, theelectric field 117 is plotted for distances up to 132 mm away, which is a rule of thumb for the farthest distance from the aperture where desired image resolution is preserved for aperture-limited systems. Ideally, the electric field should look like horizontal lines parallel to the aperture ofarray 102. For the majority of the region below the exemplary array illustrated at the top ofFIG. 3 , this is the case. Variations in amplitude and phase in theelectric field 117 are relatively minimal because theantennas 116 radiating theelectric field 117 inFIG. 3 have a relatively narrow beamwidth. By comparison, an electric field distribution along x at various distances from the imaging system would exhibit greater variations when theantennas 116 are ideal point sources. FromFIG. 3 , it is shown that while there are limited regions for the plane-wave approximation, most of the region belowarray 102 can still be used for improved imaging in accordance with embodiments of the invention. - Referring now to
FIGS. 4A, 4B, and 4C ,target 118 is a metal ball in front of the aperture ofantenna array 102 at different locations relative toantennas 116 anddetectors 120. Theimage processor 110 generates images of the metal ball based on the voltages measured at detectors 120 (e.g., Schottky diodes). InFIG. 4A , the small metal ball in clearly visible and with an indication matching the small physical size of the ball. InFIG. 4B , the metal ball is placed relatively far away but still at the center ofarray 102. The ball is clearly visible, but larger due to the expected degraded resolution, which is a property of the ω-k algorithm. And inFIG. 4C , the ball placed at the right edge ofarray 102 is not clearly visible. This is due to the electric field phase distortions at the edge ofarray 102 as described above. The images ofFIGS. 4A, 4B, and 4C indicate that thesystem 100 ofFIG. 1 is capable of imaging to a predetermined distance away from and offset fromarray 102. - In an embodiment, a printed circuit board houses 16
antennas 116 with 32 Schottky diodes (detectors 120) at the aperture ofarray 102. A signal transmitted into the board is first amplified by an HMC499LC4 RF amplifier, which is to compensate for signal loss between the amplifier andantennas 116. The output of the amplifier is then re-routed to eachantenna 116 via a series ofpassive dividers 112. The controller hardware preferablytunes microwave source 104 to 21.5-27 GHz frequency range (full range of the source). -
FIG. 5 is an exemplary image of a metal rod generated via the fabricatedantenna array 102 described above. In this instance, the rod is oriented normal to the plane ofantenna array 102 and, thus, is represented in the figure as a generally circular shape. The image ofFIG. 5 shows the circle clearly with some localized distortions. Additionally, the surrounding noise in the image is higher than in the simulations. This is usually caused by noise sources in the physical hardware not considered in simulation and amplitude imbalance between the 32 diodes. Amplitude imbalance between the diodes can be removed by proper amplitude calibration. - Overall, the
system 100 ofFIG. 1 has been shown to be capable of generating images of targets with some appreciable fidelity without the requirement of a microwave multiplexer network. - It is contemplated to make use of antenna array design principles to enhance the
electric field 117 radiated from thearray 102 and to expand the functionality ofsystem 100.FIG. 6 illustrates an alternative embodiment in whichsystem 100 comprises microwave signal amplitude and phase shifting elements 124 (e.g., attenuators, phase shifters, etc.) placed between theantenna elements 116 and thepassive divider network 112. Theadditional elements 124 permits synthesizing a more accurate plane-wave at many distances fromarray 102 by properly choosing the proper values for the amplitude andphase shifting elements 124. By synthesizing a more accurate plane-wave pattern, the approximation of the forward propagated electric field becomes the actual representation in the modified ω-k algorithm. Thus, image distortions are effectively removed. - Another use of amplitude and
phase shifting elements 124 is beam steering thearray 102 in its far field. In one instance, thephase shifter elements 124 are set to create a plane-wave in the near-field of the array, and in another instance, they are set to create a progressive phase distribution for beam scanning wide angles in the far-field. This creates a dual purpose imaging system for imaging both in the near-field and far-field of the array. - Yet another alternative embodiment of an
imaging system 100 is shown inFIG. 7 , where single pole single throw switches 126 are placed betweenpassive divider network 112 andantenna elements 116, instead of amplitude andphase shifting elements 124. The use of theswitches 126 permits selectively turning on certain antenna elements 116 (i.e., randomly turn oncertain antenna elements 116, turn on everyother antenna element 116, etc.), so the total scanning range can be extended and/or imaging resolution improved. This is an additional method for imaging close to and far fromarray 102 with thesame system 100. - In yet another embodiment, a
system 200 embodying aspects of the invention is capable of 2D imaging and employs aplanar antenna array 202. A schematic of theimaging system 200 is shown inFIG. 8 . Theimaging system 200 contains the same major components as the lineararray imaging system 100 described above. In this instance, however,system 200 employs a corporatefeed waveguide structure 212 rather than passivepower divider network 112. The corporatefeed waveguide structure 212 has much lower signal loss than the Wilkinson divider-based feed. Also, thearray 102 has a plurality (e.g., 64) of rectangular slots 216 loaded with Schottky power detectors 220 instead of thelinear array 102 of tapered slot-line antennas 116, thus allowing for 2D microwave imaging. In the present embodiment, the design operates in the 23-25 GHz frequency range, and the slot antennas 216 are loaded with power detectors 220. In an embodiment, thesystem 200 is approximately 3.6″×5.0″×2.2″ in size. - As described above,
imaging system 200 generates a pseudo plane-wave in front of theimaging array 102 but the region where a pseudo plane-wave exists becomes smaller as the distance from theimaging array 102 increases. Totest system 200, three small metal spheres are placed 40 mm, for example, in front ofarray 202. Thesystem 200 in this example is oriented with theantenna array 202 radiating up into the air. Then, a 40 mm-thick piece of construction foam is placed on top of the aperture ofantenna array 202. One metal sphere is placed in the middle of the foam where a pseudo plane-wave exists, the next metal sphere is placed at an edge of the pseudo plane-wave region, and the third metal sphere wave is placed outside the pseudo plane-wave region. The resulting image inFIG. 9 shows a clear indication of the center metal sphere, and the second sphere is darker but still visible at the lower left corner of the image. Finally, the sphere outside the pseudo plane-wave region cannot be seen, as expected. This illustrates the effect ofimaging targets 118 inside and outside the region where a pseudo plane-wave exists. - Another test determines the sensitivity of
imaging system 200 totargets 118 that have different dielectric properties (i.e., level of reflected signal from target 118). Thetarget 118 will scatter stronger or weaker signals depending on its dielectric properties. In this test, a metal sphere (strong scatterer) is placed in the upper left corner ofimaging array 202; a rubber target (moderate scatterer) placed in the center ofimaging array 202; and a plastic sphere (weak scatterer) is placed in the lower right corner ofimaging array 202. The resulting image inFIG. 10 shows a bright indication of the metal sphere. In an embodiment, there may be additional distortions directly right and below the indication of the metal sphere due to aliasing and the strong scattering from the metal sphere. The indication of the rubber target is darker but visible in the center of the image ofFIG. 10 , and the indication of the plastic sphere is barely visible in the lower right corner of the image. This image shows how different materials appear brighter or darker depending on their dielectric properties, as expected. - The image of
FIG. 11 demonstrates ability ofsystem 200 to detect relatively large metallic objects, which is crucial for security applications.FIG. 11 shows the resulting image of placing a metal key in front ofimaging system 200. In the microwave image, the basic shape and size of the key can be observed. It is contemplated to employ this imaging methodology for detecting large metallic objects for various security applications. - In addition to the embodiments described above, embodiments of the present disclosure may comprise a special purpose computer including a variety of computer hardware, as described in greater detail below.
- Embodiments within the scope of the present disclosure also include computer-readable media for carrying or having computer-executable instructions or data structures stored thereon. Such computer-readable media can be any available media that can be accessed by a special purpose computer and comprises computer storage media and communication media. By way of example, and not limitation, computer storage media include both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media are non-transitory and include, but are not limited to, random access memory (RAM), read only memory (ROM), electrically erasable programmable ROM (EEPROM), compact disk ROM (CD-ROM), digital versatile disks (DVD), or other optical disk storage, solid state drives (SSDs), magnetic cassettes, magnetic tape, magnetic disk storage, or other magnetic storage devices, or any other medium that can be used to carry or store desired non-transitory information in the form of computer-executable instructions or data structures and that can be accessed by a computer. When information is transferred or provided over a network or another communications connection (either hardwired, wireless, or a combination of hardwired or wireless) to a computer, the computer properly views the connection as a computer-readable medium. Thus, any such connection is properly termed a computer-readable medium. Combinations of the above should also be included within the scope of computer-readable media. Computer-executable instructions comprise, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing device to perform a certain function or group of functions.
- The following discussion is intended to provide a brief, general description of a suitable computing environment in which aspects of the disclosure may be implemented. Although not required, aspects of the disclosure will be described in the general context of computer-executable instructions, such as program modules, being executed by computers in network environments. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Computer-executable instructions, associated data structures, and program modules represent examples of the program code means for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represent examples of corresponding acts for implementing the functions described in such steps.
- Those skilled in the art will appreciate that aspects of the disclosure may be practiced in network computing environments with many types of computer system configurations, including personal computers, hand-held devices, multi-processor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, and the like. Aspects of the disclosure may also be practiced in distributed computing environments where tasks are performed by local and remote processing devices that are linked (either by hardwired links, wireless links, or by a combination of hardwired or wireless links) through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices.
- An exemplary system for implementing aspects of the disclosure includes a special purpose computing device in the form of a conventional computer, including a processing unit, a system memory, and a system bus that couples various system components including the system memory to the processing unit. The system bus may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. The system memory computer storage media, including nonvolatile and volatile memory types. A basic input/output system (BIOS), containing the basic routines that help transfer information between elements within the computer, such as during start-up, may be stored in ROM. Further, the computer may include any device (e.g., computer, laptop, tablet, PDA, cell phone, mobile phone, a smart television, and the like) that is capable of receiving or transmitting an IP address wirelessly to or from the internet.
- The computer may also include a magnetic hard disk drive for reading from and writing to a magnetic hard disk, a magnetic disk drive for reading from or writing to a removable magnetic disk, and an optical disk drive for reading from or writing to removable optical disk such as a CD-ROM or other optical media. The magnetic hard disk drive, magnetic disk drive, and optical disk drive are connected to the system bus by a hard disk drive interface, a magnetic disk drive-interface, and an optical drive interface, respectively. The drives and their associated computer-readable media provide nonvolatile storage of computer-executable instructions, data structures, program modules, and other data for the computer. Although the exemplary environment described herein employs a magnetic hard disk, a removable magnetic disk, and a removable optical disk, other types of computer readable media for storing data can be used, including magnetic cassettes, flash memory cards, digital video disks, Bernoulli cartridges, RAMs, ROMs, SSDs, and the like.
- Communication media typically embody computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media.
- One or more aspects of the disclosure may be embodied in computer-executable instructions (i.e., software), routines, or functions stored in system memory or nonvolatile memory as application programs, program modules, and/or program data. The software may alternatively be stored remotely, such as on a remote computer with remote application programs. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types when executed by a processor in a computer or other device. The computer executable instructions may be stored on one or more tangible, non-transitory computer readable media (e.g., hard disk, optical disk, removable storage media, solid state memory, RAM, etc.) and executed by one or more processors or other devices. As will be appreciated by one of skill in the art, the functionality of the program modules may be combined or distributed as desired in various embodiments. In addition, the functionality may be embodied in whole or in part in firmware or hardware equivalents such as integrated circuits, application specific integrated circuits, field programmable gate arrays (FPGA), and the like.
- Preferably, computer-executable instructions are stored in a memory, such as the hard disk drive, and executed by the computer. Advantageously, the computer processor has the capability to perform all operations (e.g., execute computer-executable instructions) in real-time.
- The order of execution or performance of the operations in embodiments illustrated and described herein is not essential, unless otherwise specified. That is, the operations may be performed in any order, unless otherwise specified, and embodiments may include additional or fewer operations than those disclosed herein. For example, it is contemplated that executing or performing a particular operation before, contemporaneously with, or after another operation is within the scope of aspects of the disclosure.
- Embodiments may be implemented with computer-executable instructions. The computer-executable instructions may be organized into one or more computer-executable components or modules. Aspects of the disclosure may be implemented with any number and organization of such components or modules. For example, aspects of the disclosure are not limited to the specific computer-executable instructions or the specific components or modules illustrated in the figures and described herein. Other embodiments may include different computer-executable instructions or components having more or less functionality than illustrated and described herein.
- When introducing elements of aspects of the disclosure or the embodiments thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including”, and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
- Having described aspects of the disclosure in detail, it will be apparent that modifications and variations are possible without departing from the scope of aspects of the disclosure as defined in the appended claims. As various changes could be made in the above constructions, products, and methods without departing from the scope of aspects of the disclosure, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
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